Air heater for fuel burners



Nov. 6, 1923.

H. s. FARQUHAR AIR HEATER FOR FUEL BURNERS Filed April 19, 1925 HENRY S.FARQUHAR, F WAYNE, PENNSYLVANIA, ASSIGNOR TO THE BALDWIN LOCOMOTIVEWORKS, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

AIR HEATER FOR FUEL BURNEBS.

Application filed April 19, 1923. Serial No. 683,177.

T 0 all whom it may concern:

Be it known that I, HENRY S. FARQU'HAR,

a citizen of the United States, residing in Wayne, Radnor Township,Delaware County, Pennsylvania, have invented certain Improvements in AirHeaters for Fuel Burners, of which the following is a specification.

My invention relates to certain improvements in air heaters for fuelburners located in the flue of a furnace.

The object of my invention is to design the preheating apparatus so thatthe air will travel in a hehcal path therethrough, caus- 15 ing the airto impinge upon the outer surface of the preheater, which quicklyincreases the temperature of the air.

In the accompanying drawings:

'Fig. 1 is a vertical sectional view of the upper portion of an oilburning furnace, showing the air heater partly in section on the line1-1, Fig. 2; and Fig. 2 is a sectional plan view on the line 2-2, Fig.1.

1 is the upper portion of an oil furnace.

2 is the stack through which the products of combustion pass from thefurnace. 3 is a cylindrical preheater, preferably made of metal. Passingthrong this preheater'is a vertical flue 4. The preheater 1s less indiameter than the stack so that the products of combustion pass around,the preheater, heating the outer walls to a high degree. The products ofcombustion also pass through the flue 4's The preheater is closed at theup per end byan annular cap plate 5 and at the lower end by an annularcap plate 6. 7 is an air pipe through which cold air passes to the upperend of the preheater. It will be noticed that this air pipe communicateswith the preheater at one side of the center, as clearly shown in Fig.2, and that it-has a suitable valve 8 for controlling the amount of airpassing to the preheater, which is under pressure.

Communicating with the lower end of the air heater is an outlet pipe 9for the preheated air. This pipe leads to a burner of any of theordinary ty es. This pipe also communicates with the ower end of the airheater and is arran ed tangentially, so that, when cold air is admittedto the preheater under pressure, it circulates in a helical path fromthe upper end thereof to the lower sired and is supported in the flue,in the present instance, by brackets 10, which rest on one of thecourses of the brick work of the flue, as clearly shown in Fig. 1. Othermeans may be used to support the air heater, if desired.

I claim: 7

1. The combination in a heater for preheating air for a furnace, of astack communicating with the furnace and through which the products ofcombustion pass from the furnace; a preheater located in the stack andaround which the products of combustlon pass; an air inlet pipecommunicating wlth one end of the preheater; and an outlet pipecommunicating with the other end thereof, said pipes being arrangedtangentially to the preheater so that air, under pressure, admitted tothe preheater passes through it in a helical path.

' 2. The combination in a furnace, of a stack; a cylindrical preheaterlocated in the stack; an inlet pipe communicating with the upper end ofthe preheater for the air under pressure; an outlet pipe at the lowerend of $5 the preheater for heated air,'the two pies communicating withthe preheater and 5-. ing arranged tangentially in respect thereto, sothat the air passing down through the preheater travels in a helicalpath and impinges upon the inner surface of the walls of the preheater.

3. The combination in a furnace, of a stack; a cylindrical preheaterlocated in the stack, said preheater being less in diameter 95 than thestack so as to provide a passage around the preheater for the productsof combustion; an inlet pipe communicating with one end of thepreheater; an outlet pipe communicating with the other end thereof, saidpipes being arranged tangentially in respect thereto so as to cause airunder pressure to travel in a helical path and impinge upon the innersurface of the preheater in its passage to theoutlet pipe.

4. The combination of, a furnace; a stack communicating therewith; apreheater l0- cated in the stack, said preheater being less in diameterthan the stack; a flue extending longitudinally through the preheater;an inlet pipe communicating with the upper end of the preheater; anoutlet pipe communicating with the. lower end thereof; and a valveEA'MAZQ for regulating the flow of air under pressure to the preheater,said pipes being arranged tangentially in respect to the preheater so as10 to cause the air in circulation to travel in a helical path throughthe preheater.

HENRY S. FARQUHAR.

